The present invention relates to an outer rail for attaching two lateral retention webs of an intermediate rail to construct a base for wall plate covering.
Such bases form a framework for wall plate covering and may today find application in both non-bearing and bearing walls, and both interior and exterior walls. However, this type of walls traditionally serves as partition or room divider. It may be provided with doors or windows. As plate covering plaster or gypsum boards are often used. The boards are typically coated with a cardboard layer contributing to distribution of surface tensions such that the porous board can be handled on the construction site and be screwed onto the underlying construction without breaking. These boards are typically produced with widths of 900 mm or 1200 mm.
Prior art rail systems for constructing a base for wall plate covering typically comprise two kinds of elements, namely outer rails and intermediate rails. The outer rails extend in a longitudinal direction and have a U-shaped cross section formed by a transverse connecting part connecting two opposed lateral retention webs. The intermediate rails often have a C-shaped cross section with two lateral screw webs.
When mounting the base the outer rails are typically fastened along ceiling and floor with the “openings” of the outer rails facing each other. An outer rail is therefore frequently used along the floor and correspondingly along the ceiling. The intermediate rails are then placed vertically between the outer rails and are attached to the outer rails at top and bottom. Subsequently, insulation may be mounted between the intermediate rails, and the plates or boards can be mounted by means of insertion of self-tapping screws through the plates and into the screw webs and/or retention webs of the intermediate and outer rails. It is also possible to attach the boards or plates with glue.
A multitude of methods for attaching the intermediate rails to the outer rails are known in the prior art. In the most widespread method the distance between the intermediate rails is set out by markings on each of the top and bottom outer rails. The markings are drawn by a workman after having made suitable measurements. Then the intermediate rails are positioned between the outer rails, after which they are attached by means of fixing tongs that cut a collared hole through both sections. A number of drawbacks are associated with this method. Most noteworthy, the modular dimensions between the intermediate rails may easily deviate, whereby the associated plate cannot be screwed on the intermediate rails with the required exact dimensions from screws to plate edge. Further, the connections between the rails are of unsatisfactory strength so that the self-tapping screws often do not get hold of the screw webs or retention webs, especially at the end parts of the intermediate rails. Also, the method is time-consuming and troublesome.
EP 1267008 A discloses an outer rail with a strip-formed retention device or tongue, which has been cut out from the outer rail. The tongue extends inclined from the retention web of the outer rail. An intermediate rail comprises a lateral screw web that extends into a flange extending inwards from a distal end of the screw web. The tongue comprises at a central part a curvature forming a depression into which the flange slides to attach the latter by means of resilience of the retention device.
Other examples of prior art rail systems are found in WO 2009/106083 A, U.S. Pat. No. 3,680,271 and U.S. Pat. No. 3,720,995.
On this background the object of the invention is to provide a cost-effective, stable and flexible outer rail design for use in system for constructing a base for wall plate covering that can be rapidly mounted.